This invention relates to a storage tank dehydration system, and particularly a quick connect and disconnect, noncorrosive, hygroscopic-agent container dehydration apparatus.
Large storage tanks for petroleum, chemicals and other liquids are typically located with exposure to the environment. Consequently, when portions of the liquid are drained from the tank, air is allowed to enter the tank to replace the liquid and thereby prevent a disruptive internal negative pressure. Because the air is from the surrounding environment, it contains moisture in varying amounts depending upon the temperature and humidity conditions at the time. Consequently, undesired moisture is entrained into the tank to react with the chemicals, dilute the remaining liquid, contaminate the contents and/or corrode the storage tank. At present, the accepted technique for limiting this adverse moisture entrance is to threadably mount or weldably attach to the air inlet pipe a metal container filled with a hygroscopic agent such as calcium chloride. Such vessels rapidly corrode, making such partially or totally useless in a short time. The corroded walls of the container can cause the hygroscopic material to undesirably fuse and bridge therein and sometimes even plug the apparatus against air flow. Moreover, since the corroded vessel and connections are very difficult to remove and refill, they are too often purposely neglected, to the detriment of the user of the storage tank contents.